1. Field of the Invention
The invention relates to a process for shutting off a motor vehicle heating device in which a liquid heat exchange medium is heated by a heating device, and is delivered to a heat exchanger of the heating device by means of a circulating pump that is driven by an electric motor, with at least one control device which controls the operation of heating device, and at least partially also the operation of circulating pump, and to which a signal regarding an operating fault of the components triggered by it can be sent via at least one signal line. The invention also relates to a process for controlling such a heating device so as to prevent its overheating.
2. Description of Related Art
A motor vehicle heating device operated with a liquid heat exchange medium is known, for example, from German Patent No. DE-C2 35 21 372. In it, the action of a circulating pump for delivery of the liquid heat exchange medium to a heat exchanger of the heating device is connected to the action of the control device of the motor vehicle heating device such that, via a signal sent to the control device, in this case, a temperature signal at the output of the heat exchanger, the rpm of the circulating pump is controlled. In another motor vehicle heating device, known from DE-A1 38 29 244 and corresponding U.S. Pat. No. 4,944,454, a signal which indicates overheating of the heating device is acquired by means of a sensor attached to the heat exchanger and is sent to the control device. This acquisition of a case of overheating functions only relatively late when the system is not filled with liquid heat exchange medium or when the system is not adequately vented and for the air bubbles associated therewith so that, in these cases, the heating device or the recirculating pup can be damaged.